The invention relates to a method and a device for yarn division on a warping machine. A method and a device of this type serve to wind several groups of warp yarns onto the warping drum. The yarn division can additionally serve to create yarn crossings, which later facilitate further working, for example the tieing together of warp yarn ends. When sizing the warp yarns, the yarn division can also ensure that the warp yarns can be guided through the size bath with sufficient separation from one another.
The insertion of separating elements between divided yarn strips is in many cases still carried out manually Methods and devices to carry out this process automatically are known, however. For example, according to CA-A-662 368, a dividing cord is pulled through the consecutively wound up warp strip rows on the drum, with the aid of a steel heald shaft. After each warp strip is completely wound, the steel heald shaft, and with it the attached dividing cord, is pulled further by one warp strip width, with the aid of a special device. The disadvantage of this method is that individual demarkation of the individual strips is not possible because the dividing cord is lead through all the warp strips of the warping drum at the same time A further disadvantage exists, in that with increasing winding radius, the pressure of the windings increases, so that the dividing cord can only be pulled with a large application of force, with the associated risk of yarn damage.
This process is therefore only employed for short warps, where relatively short warp lengths are wound up.
A further automatic method has been made known, for example, through JP-B-62-2055. According to this method two parallel tubes are pushed over the opened yarn strip, whereby the tubes in the engaged position are connected by a firmly fixed tube bend which incorporates a slot in its inner radius. Through either compressed air or a vacuum, a separating yarn is subsequently introduced into one tube, lead around through the tube bend, and back down the other tube, so that a yarn loop can be formed, which is automatically tieable after the two tubes are withdrawn. With this method even individual warp strips can be separated. Naturally, this method is extremely difficult to manipulate, since deflection of the separating yarn through 180 degrees and the formation of the loop is very prone to malfunction.